Binaural Multi-Channel Decoding for Upmix Energy Error Control
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Solution Overview
Problem
Existing methods for generating binaural signals from multi-channel audio face challenges in energy conservation and spectral coloring due to non-energy-conserving upmixing rules, especially when using HRTF filters with downmixed signals and spatial parameters.
Innovation Solution
A multi-channel decoder is developed that calculates a gain factor to correct energy errors in binaural signal generation by utilizing upmix rule information and HRTF filter characteristics, allowing for energy-corrected binaural signal production without fully rendering multichannel signals, thereby reducing spectral coloring artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If non-energy-conserving upmixing rules are used for binaural signal generation, then computational efficiency is improved, but energy errors and spectral coloring artifacts occur
Solution Approach 1:
The patent introduces an energy correction factor as an intermediary element that mediates between the computationally efficient non-energy-conserving upmixing rules and the desired energy conservation. This factor is calculated based on HRTF filter characteristics and applied to correct the energy errors introduced by the simplified upmixing process, thereby maintaining computational efficiency while eliminating energy losses and spectral coloring artifacts.
2Device complexity
If non-energy-conserving upmixing rules are used for binaural signal generation, then processing complexity is reduced, but spectral coloring artifacts increase
Solution Approach 1:
The energy correction factor serves as an intermediary that eliminates spectral coloring artifacts without increasing processing complexity. By calculating this factor based on pre-stored HRTF filter characteristics and applying it as a simple scaling operation, the patent removes the harmful spectral coloring effects while maintaining the low computational complexity of the non-energy-conserving upmixing approach.
Solution Approach 2:
The patent changes the energy parameter of the upmixed signal by applying the energy correction factor. This parameter change compensates for the energy errors and spectral coloring introduced by the simplified upmixing rules, thereby improving audio quality without adding significant processing complexity.
3Manufacturing precision
If energy correction is applied using HRTF filter characteristics, then audio quality is improved, but computational load increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing HRTF filter characteristics that incorporate energy information. During runtime, the energy correction factor is derived from these pre-processed characteristics rather than performing full HRTF convolutions, thereby improving audio quality while minimizing the increase in computational load during actual audio processing.
Data Source
AI summary
A multi-channel decoder for generating a binaural signal from a downmix signal using upmix rule information on an energy-error introducing upmix rule for calculating a gain factor based on the upmix rule information and characteristics of head related transfer function based filters corresponding to upmix channels. The one or more gain factors are used by a filter processor for filtering the downmix signal so that an energy corrected binaural signal having a left binaural channel and a right binaural channel is obtained.